Answer:
The correct answer is:
<em>(1) It is important that the sample is dissolved in just enough hot solvent. </em>
Explanation:
The process of recrystallization is important to eliminate the impurities and to obtain better crystals of the solid. The solvent used to perform the recrystallization must have a high dissolution power of the substance to be recrystallized and a low dissolution power of the impurities. This is in order to eliminate most impurities. Furthermore, <em>It is important that the sample is dissolved in just enough hot solvent </em>because this should be easy to remove after the recrystallization and the crystal should form easily when the solution cools. Also, it is better to add the hot solvent to solubilize the crystals and keep the impurities insoluble, instead of adding the cold solvent and heating the solution. Additionally, the process of cooling the solution must be done slowly to obtain large and fewer crystals. A fast ice-cooling will form smaller crystals.
Answer:
The atomic theory has changed over time as new technologies have become available. Scientific knowledge builds on past research and experimentation. 400 B.C. Democritus, a philosopher in ancient Greece, began the search for a description of matter.
Explanation:
Answer:
Since the relationship between amino acid and codon bases would be the values of 3 nitrogenous bases per 1 amino acid.
knowing this relationship what you would do is simply multiply 146 x 3 to find the number of codon bases which would be C. 438.
The answer is A) Water has surface tension.
This is the correct answer because water allows animals and really light items to rest upon the top of the water.
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Answer is: the collision theory.
The collision theory states that a certain fraction of the collisions (successful collisions) cause significant chemical change.
The successful collisions must have enough energy (activation energy), on this diagram that energy is represented with arrow up.
Chemical bonds are broken (between blue and red-black molecules) and new bonds are formed (between blue-red and blue-black molecules), as it is represented on diagram.